GTTF: Fix a few cases of very likely broken code between fork() and exec()
GTTF: Fix a few cases of very likely broken code between fork() and exec()

I took another look at http://crbug.com/60426, and decided to also
review the LaunchApp code in process_util. It turns out that
the child code after fork() contained things like "return false",
rather not what was intended (I replaced it with _exit(127)).

There are some other cases where we possibly retained some
signal handlers. The new code also resets them to defaults.

I don't expect it to fix the referenced bug, but those
"obvious" problems can only make it worse.

BUG=60426
Review URL: http://codereview.chromium.org/6801047

git-svn-id: de016e52bd170d2d4f2344f9bf92d50478b649e0@80927 0039d316-1c4b-4281-b951-d872f2087c98

Pluto-tv/chromium-crosswalk,hgl888/chromium-crosswalk-efl,junmin-zhu/chromium-rivertrail,markYoungH/chromium.src,krieger-od/nwjs_chromium.src,junmin-zhu/chromium-rivertrail,mogoweb/chromium-crosswalk,ondra-novak/chromium.src,keishi/chromium,keishi/chromium,ondra-novak/chromium.src,littlstar/chromium.src,ondra-novak/chromium.src,axinging/chromium-crosswalk,TheTypoMaster/chromium-crosswalk,PeterWangIntel/chromium-crosswalk,PeterWangIntel/chromium-crosswalk,rogerwang/chromium,dushu1203/chromium.src,keishi/chromium,fujunwei/chromium-crosswalk,zcbenz/cefode-chromium,patrickm/chromium.src,ondra-novak/chromium.src,krieger-od/nwjs_chromium.src,krieger-od/nwjs_chromium.src,krieger-od/nwjs_chromium.src,hgl888/chromium-crosswalk,zcbenz/cefode-chromium,anirudhSK/chromium,patrickm/chromium.src,rogerwang/chromium,PeterWangIntel/chromium-crosswalk,Just-D/chromium-1,timopulkkinen/BubbleFish,jaruba/chromium.src,anirudhSK/chromium,krieger-od/nwjs_chromium.src,mogoweb/chromium-crosswalk,Pluto-tv/chromium-crosswalk,hujiajie/pa-chromium,robclark/chromium,TheTypoMaster/chromium-crosswalk,ChromiumWebApps/chromium,Fireblend/chromium-crosswalk,Chilledheart/chromium,anirudhSK/chromium,pozdnyakov/chromium-crosswalk,pozdnyakov/chromium-crosswalk,mohamed--abdel-maksoud/chromium.src,markYoungH/chromium.src,Pluto-tv/chromium-crosswalk,rogerwang/chromium,TheTypoMaster/chromium-crosswalk,zcbenz/cefode-chromium,dushu1203/chromium.src,robclark/chromium,timopulkkinen/BubbleFish,crosswalk-project/chromium-crosswalk-efl,jaruba/chromium.src,dednal/chromium.src,nacl-webkit/chrome_deps,Fireblend/chromium-crosswalk,Just-D/chromium-1,ltilve/chromium,M4sse/chromium.src,crosswalk-project/chromium-crosswalk-efl,Fireblend/chromium-crosswalk,Chilledheart/chromium,zcbenz/cefode-chromium,hgl888/chromium-crosswalk,ltilve/chromium,keishi/chromium,mohamed--abdel-maksoud/chromium.src,pozdnyakov/chromium-crosswalk,Jonekee/chromium.src,dushu1203/chromium.src,Fireblend/chromium-crosswalk,hujiajie/pa-chromium,axinging/chromium-crosswalk,patrickm/chromium.src,junmin-zhu/chromium-rivertrail,ChromiumWebApps/chromium,dednal/chromium.src,hujiajie/pa-chromium,Just-D/chromium-1,dednal/chromium.src,M4sse/chromium.src,hgl888/chromium-crosswalk,timopulkkinen/BubbleFish,Jonekee/chromium.src,Jonekee/chromium.src,Jonekee/chromium.src,keishi/chromium,Pluto-tv/chromium-crosswalk,mohamed--abdel-maksoud/chromium.src,hujiajie/pa-chromium,zcbenz/cefode-chromium,ondra-novak/chromium.src,hgl888/chromium-crosswalk,nacl-webkit/chrome_deps,ondra-novak/chromium.src,hgl888/chromium-crosswalk-efl,dushu1203/chromium.src,jaruba/chromium.src,mogoweb/chromium-crosswalk,M4sse/chromium.src,axinging/chromium-crosswalk,pozdnyakov/chromium-crosswalk,dushu1203/chromium.src,crosswalk-project/chromium-crosswalk-efl,dushu1203/chromium.src,rogerwang/chromium,rogerwang/chromium,hgl888/chromium-crosswalk-efl,axinging/chromium-crosswalk,PeterWangIntel/chromium-crosswalk,jaruba/chromium.src,keishi/chromium,M4sse/chromium.src,pozdnyakov/chromium-crosswalk,dednal/chromium.src,axinging/chromium-crosswalk,TheTypoMaster/chromium-crosswalk,timopulkkinen/BubbleFish,timopulkkinen/BubbleFish,rogerwang/chromium,timopulkkinen/BubbleFish,hgl888/chromium-crosswalk,M4sse/chromium.src,TheTypoMaster/chromium-crosswalk,chuan9/chromium-crosswalk,krieger-od/nwjs_chromium.src,chuan9/chromium-crosswalk,robclark/chromium,fujunwei/chromium-crosswalk,markYoungH/chromium.src,Chilledheart/chromium,robclark/chromium,crosswalk-project/chromium-crosswalk-efl,mohamed--abdel-maksoud/chromium.src,Just-D/chromium-1,bright-sparks/chromium-spacewalk,krieger-od/nwjs_chromium.src,ondra-novak/chromium.src,TheTypoMaster/chromium-crosswalk,Chilledheart/chromium,fujunwei/chromium-crosswalk,ltilve/chromium,dushu1203/chromium.src,nacl-webkit/chrome_deps,littlstar/chromium.src,anirudhSK/chromium,jaruba/chromium.src,nacl-webkit/chrome_deps,Just-D/chromium-1,bright-sparks/chromium-spacewalk,PeterWangIntel/chromium-crosswalk,axinging/chromium-crosswalk,chuan9/chromium-crosswalk,hujiajie/pa-chromium,ChromiumWebApps/chromium,robclark/chromium,rogerwang/chromium,ltilve/chromium,zcbenz/cefode-chromium,robclark/chromium,littlstar/chromium.src,anirudhSK/chromium,keishi/chromium,dednal/chromium.src,pozdnyakov/chromium-crosswalk,mogoweb/chromium-crosswalk,dushu1203/chromium.src,dednal/chromium.src,markYoungH/chromium.src,bright-sparks/chromium-spacewalk,timopulkkinen/BubbleFish,crosswalk-project/chromium-crosswalk-efl,anirudhSK/chromium,Just-D/chromium-1,krieger-od/nwjs_chromium.src,dushu1203/chromium.src,PeterWangIntel/chromium-crosswalk,ChromiumWebApps/chromium,pozdnyakov/chromium-crosswalk,anirudhSK/chromium,hgl888/chromium-crosswalk,bright-sparks/chromium-spacewalk,mogoweb/chromium-crosswalk,Fireblend/chromium-crosswalk,Pluto-tv/chromium-crosswalk,mohamed--abdel-maksoud/chromium.src,jaruba/chromium.src,fujunwei/chromium-crosswalk,jaruba/chromium.src,chuan9/chromium-crosswalk,fujunwei/chromium-crosswalk,pozdnyakov/chromium-crosswalk,rogerwang/chromium,littlst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